Change in depositional environment of Maharashtra coast, central west coast of India

Abstract

Deposition of organic matter in nearshore and offshore regions largely depends upon the contribution from terrestrial inputs. Rivers are the major pathways of organic matter to these regions. Any change in fluvial or estuarine inputs therefore will significantly affect the biogeochemical processes operating in nearshore and offshore environments. Significant change in distribution patterns of grain size, organic carbon, TOC/TN ratio, diatom assemblages and carbon isotope ratio values have been noted in the cores collected from Khonda creek, Dudh creek, Vaitarna estuary, Amba estuary, Kundalika estuary, Rajapuri creek and Savitri estuary. All these estuaries and creeks located along central west coast of India indicated a transition from river dominated depositional environment in the past to marine dominated depositional environment in recent years. Since these estuaries and creeks are the pathways of terrestrial material load to eastern Arabian Sea region, decrease in input of terrestrial material load over time has significantly affected the biogeochemical processes operating in this region.